Which chemical reaction produces ortho-hydroxybenzoic acid, the primary reaction product used as a raw material for medications?
Solution:
The correct answer is Kolbe’s reaction (Kolbe–Schmitt reaction).
Explanation:
Ortho-hydroxybenzoic acid (salicylic acid) is prepared by heating sodium phenoxide with carbon dioxide (CO₂) under pressure (about 4–7 atm) at around 400 K. The intermediate formed is sodium salicylate, which on acidification gives salicylic acid.
C₆H₅ONa + CO₂ → C₆H₄(OH)COONa →(H⁺)→ C₆H₄(OH)COOH
Importance:
Salicylic acid is an important compound used in the manufacture of several medicines:
- Aspirin (acetylsalicylic acid): Used as a pain reliever, fever reducer, and anti-inflammatory drug
- Methyl salicylate: Used in topical ointments for muscle pain relief
Why other options are incorrect:
- Reimer–Tiemann reaction: Produces salicylaldehyde (–CHO group), not salicylic acid (–COOH group)
- Stephen reaction: Used to prepare aldehydes from nitriles
- Friedel–Crafts reaction: Used for alkylation or acylation of aromatic rings, not for forming hydroxy acids
Correct Answer: Kolbe’s reaction
Important Questions from Chemical Reaction
Which of the following statement is/are true?
I. In physical change new substance is formed. substance is formed.
II. In chemical change no new substance is formed.
Which of the following cells involves similar chemical reactions?
The information not obtained from balanced chemical equation is
Oxygen cannot be obtained by which one of the following methods?
Which is the most reactive metal?
